DRILL BIT FOR MAKING HOLES WITH REAR TRIMMING Russian patent published in 2019 - IPC B28D1/14 B23B51/08 

FIELD: technological processes.

SUBSTANCE: invention relates to a drill for making a hole with rear trim, in particular in facing panels made of ceramics, stone, concrete and other brittle materials, which are fixed on the building facades with the help of an expandable anchor. In the drill bit, having a cylindrical cutting head fixed on the shank with an offset from the drill axis of rotation, part of which, most distant from drill rotation axis, is chamfered to form conical part protruding beyond cylindrical part and intended for back cutting, and a channel for cooling liquid passing in the shank along the drill rotation axis and inclined relative to the drill rotation axis in the cutting head with the outlet hole on its end surface, inclined channel for cooling liquid is made with outlet hole on end surface of cutting head in zone of sector with central angle α=30–45°, wherein axis of symmetry of sector passes at an angle β=60–90° to axis of symmetry of conical part of cutting head passing through drill rotation axis.

EFFECT: such drill bit has improved strength characteristics and operating conditions, providing timely removal of sludge from cutting zone, due to which significantly increases service life of tool.

3 cl, 3 dwg